Note 3 - Variable Interest Entity - Schedule of Total Assets, the Maximum Exposure to Loss, Value of the Assets and Liabilities in EAM (Details) - USD ($)		Jul. 31, 2017	Apr. 30, 2017
Equity Method Investments		$ 58,454,000	$ 58,223,000
EAM Trust [Member]
Equity Method Investments	[1]	58,454,000	58,223,000
Value Line Liabilities
Value Line Liabilities		58,454,000	58,223,000
VIE Assets		$ 60,692,000	$ 60,432,000

[1] Reported within Long Term Assets on the Consolidated Condensed Balance Sheets.